Filaria zoogeography in Africa: ecology, competitive exclusion, and public health relevance

Molyneux, David; Mitre, Edward; Bockarie, Moses J.; Kelly-Hope, Louise A.

doi:10.1016/j.pt.2014.02.002

Cited by 23 publications

(21 citation statements)

References 46 publications

(55 reference statements)

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“…This interaction, probably immune in nature, can influence the different patterns of prevalence observed [32]. Nonetheless, the fact that both species can simultaneously complete their life cycles in the same host suggests the existence of competitive exclusion, as it seems to occur in human filariae in Africa [33]. …”

Section: The Episystem Of Dirofilariasismentioning

confidence: 99%

The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View

Simón

González‐Miguel

Diosdado

et al. 2017

BioMed Research International

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Vector-borne transmitted helminthic zoonosis affects the health and economy of both developing and developed countries. The concept of episystem includes the set of biological, environmental, and epidemiological elements of these diseases in defined geographic and temporal scales. Dirofilariasis caused by different species of the genus Dirofilaria is a disease affecting domestic and wild canines and felines and man, transmitted by different species of culicid mosquitoes. This complexity is increased because Dirofilaria species harbor intracellular symbiont Wolbachia bacteriae, which play a key role in the embryogenesis and development of dirofilariae and in the inflammatory pathology of the disease. In addition, the vector transmission makes the dirofilariasis susceptible to the influence of the climate and its variations. The present review addresses the analysis of dirofilariasis from the point of view of the episystem, analyzing the complex network of interactions established between biological components, climate, and factors related to human activity, as well as the different problems they pose. The progress of knowledge on human and animal dirofilariasis is largely due to the multidisciplinary approach. Nevertheless, different aspects of the disease need to continue being investigated and cooperation between countries and specialists involved should be intensified.

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Section: The Episystem Of Dirofilariasismentioning

confidence: 99%

The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View

Simón

González‐Miguel

Diosdado

et al. 2017

BioMed Research International

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“…The filarial infections of humans in Africa demonstrate a wide spectrum of pathology and epidemiology as well as a diversity of vectors, ecology and distribution [ 1 ]. Imposed on this already complex pattern have been large-scale intervention programmes, ongoing for 40 years, initially for onchocerciasis, and since 2000 for lymphatic filariasis (LF) [ 2 – 7 ].…”

Section: Background To Large-scale Programmesmentioning

confidence: 99%

Multidimensional complexities of filariasis control in an era of large-scale mass drug administration programmes: a can of worms

Molyneux

Hopkins

Bradley

et al. 2014

Parasites & Vectors

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The impact of control and elimination programmes by mass drug administration (MDA) targeting onchocerciasis and lymphatic filariasis (LF) in sub-Saharan Africa over the last two decades has resulted in significantly reduced prevalence and intensity of infection, with some areas interrupting transmission. However, given that these infections are often co-endemic and the drugs (either ivermectin alone or combined with albendazole) also impact on soil transmitted helminths (STH), the importance of this, in terms of reaching the global goals has not been assessed. The additional problem posed by Loa loa, where ivermectin cannot be safely administered due to the risk of serious adverse events compounds this situation and has left populations drug naïve and an alternative strategy to eliminate LF is yet to be initiated at scale. Here, we present a series of operational research questions, which must be addressed if the effectiveness of integrated control of filarial and helminth infections is to be understood for the endgame. This is particularly important in the diverse and dynamic epidemiological landscape, which has emerged as a result of the long-term large-scale mass drug administration (or not). There is a need for a more holistic approach to address these questions. Different programmes should examine this increased complexity, given that MDA has multiple impacts, drugs are given over different periods, and programmes have different individual targets.

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“…Importantly, here we show that they also geographically coincide with the defined SAE areas, which are not located in the dense forested areas where high loiasis dominates [20], nor along the Congo River where high onchocerciasis dominates - but somewhere in between - in the intermediate transmission zone where neither parasite appears to dominate. This raises important questions about parasite co-existence and competition [25], and the role of environmental and demographic factors influencing the main vectors, and the intensity and overlap of transmission.…”

Section: Discussionmentioning

confidence: 99%

Innovative tools for assessing risks for severe adverse events in areas of overlapping Loa loa and other filarial distributions: the application of micro-stratification mapping

Kelly-Hope

Cano

Stanton

et al. 2014

Parasites & Vectors

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BackgroundThe wide distribution of Loa loa infection (loiasis) throughout the Democratic Republic of Congo (DRC) is a major obstacle to the plans to eliminate onchocerciasis and lymphatic filariasis (LF) because the standard drug regime is dependent on ivermectin, which cannot be used in co-endemic areas due to the risk of severe adverse events (SAEs). A better understanding of the micro-epidemiology, overlapping low and high risk areas, and how they relate to SAEs is critical to ensure safe and effective treatment.FindingsBased on published data from the Bas Congo Province in DRC, this study used geographical information systems (GIS) to re-map and analyse onchocerciasis and loiasis prevalence (<20%, 20 to 40%, >40%) at 144 sites in relation to health district areas reporting SAEs. The new maps highlighted the contrasting patterns of the high prevalence sites, and significant geographical overlap between low onchocerciasis and high loiasis sites. Statistical analyses found that sites with medium to high loiasis prevalence were 10 to 16 times more likely to be in a SAE area than those with low prevalence of loiasis. Sites where both onchocerciasis and loiasis prevalence was >20% were also associated with SAE areas.ConclusionsCollaborative efforts between the national onchocerciasis and LF programmes are critical as plans to scale interventions are moving forward and thus, alternative strategies needed in loiasis co-endemic areas which may include the new L. loa test and treat strategy using the Cellscope, or interventions such as integrated vector management, or anti Wolbachia therapy using doxycycline.

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Filaria zoogeography in Africa: ecology, competitive exclusion, and public health relevance

Cited by 23 publications

References 46 publications

The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View

The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View

Multidimensional complexities of filariasis control in an era of large-scale mass drug administration programmes: a can of worms

Innovative tools for assessing risks for severe adverse events in areas of overlapping Loa loa and other filarial distributions: the application of micro-stratification mapping

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